ABS stays lit on '95 Tahoe

[pissedoffmonkey]

A couple days ago I noticed the ABS light was staying on while driving. When the ignition is switched from off to the on position the ABS light (along with check engine, batt, brake lights) comes on. Once the engine is started, all the idiot lights go off after a second and then the ABS light comes on and stays on. It stays on while driving and never turns back off until the engine is shut off. I searched for other threads on this topic and tried a few things like:

-Check brake fluid level (although this shouldn't matter, right?). It is above the fill about halfway on the view window.
-Check to make sure all fuses behind dash panel are snug.
-Check to make sure all fuses under the hood in the black box by ABS module are snug. Also, clean contacts a little on 60A ABS fuse. Tested 60A ABS fuse with ohm meter (showed 0.7ohms, which tells me it isn't blown or bad).
-Unplugged the 2-wire plug (power?) to ABS module in an attempt to force the sensors to reset.
-Made sure parking brake wasn't engaged (rarely use it and probably not related to ABS light anyway)

I put on new pads and rotors up front about 6mos ago and the drums in the rear have plenty of meat. The ABS light doesn't flash any cryptic codes... so I am kind of stumped. I have not noticed any difference in stopping ability or pedal feel, but I haven't gotten on them hard recently to test the ABS either.

Truck specs:
1995 Chevy K1500 Tahoe
5.7L TBI
4WD
4L60 trans
4 wheel ABS (so says CARFAX, at least)
115k miles

Any and all help is appreciated.

[Mark in INdiana]

Did you reset the ABS wheels speed sensors when you replaced the rotors? You just push them up against the tone rings. Then the tone rings 'bump' the sensors back while you drive to set the running clearance. Your best bet is to have the ABS ECU scanned to the fault code(s).

[NEUMANNZZ]

usually with the light on the antilock system wont work. but your brakes will still work. might have to take it in to get it scanned for codes. to check for codes you will need a jumper wire. install the wire at the diagnostic link in terminal "H" and "A" for two seconds the remove. count the flashing lights. they should be 2 digit codes. ex: 2 flashes followed by 4 flashes is code 24. to reset the system turn on ignition put jumper wire in terminal "H" and "A" for two seconds then remove jumper wire. a good indication is when both the antilock and brake lamps light then turn off. let me know the results.

[NEUMANNZZ]

ALMOST FORGOT HOPEFULLY YOU HAVE OBDI AND NOT OBDII (DONT USE THE JUMPER WIRE FOR OBDII). 94 model S- Trucks were OBDII mostly Blazers and Jimmys but not all if the connector is a square connector it is OBDI if oval in shape and 16 pins it is OBDII

[pissedoffmonkey]

I don't know what an ABS wheel speed sensor is, so no, I didn't reset them if they require something special. I am pretty sure the light hasn't been on for the last 6mos, though.

I must be a n00b, because I don't know where the diagnostic link is. I can just use a small wire to put the system into diagnostic mode, right?

[NEUMANNZZ]

Yes The Connector Is Below The Steering Wheel, Check To Make Sure Its The Right Connector As Stated Above Before You Start.

[NEUMANNZZ]

The Wheel Speed Sensor Is Behind The Rotor. The Wheel Tone Is Also Behind The Rotor It Looks Like A Gear With Teeth. Just Look For A Wire Going To The Front Wheels On The Upper Control Arm. Follow It To The Sensor.

[pissedoffmonkey]

Well, it is the last year of TBI in the full size SUVs/trucks, so does that mean it is OBD I?

How does the speed sensor work? Does it count the revolutions? Why does it need to be reset after changing the rotors?

[Reaper]

Some vehicles made in 1995 were OBDI, but had the OBDII ALDL port. Starting in 1996, all vehicles were OBDII, but our 95's are in fact OBDI. Therefore, you can use a wire or paperclip to jump the terminals and read codes. I have an ABS light as well, but I haven't started troubleshooting. Let us know how it goes.

[scrapen]

when i had my chevy car when i was like 16 my cousin and i replaced the brakes on it and he noticed that the ABS sensor on it was bad or broken or whatever and it was the reason why my abs light had come on in the car.....i would assume this could be a similar case....although i'm not sure if it's different from the trucks though because i never took notice on either of my '97's

[paoutsider]

The Wheel Speed Sensor Is Behind The Rotor. The Wheel Tone Is Also Behind The Rotor It Looks Like A Gear With Teeth. Just Look For A Wire Going To The Front Wheels On The Upper Control Arm. Follow It To The Sensor.

ive been reading along here cuz my abs light came on and has stayed on just the other day after i replaced the pads and rotors. i have a 95 silv 4x4 z71

so what do i need to do to adjust the sensor? just push on it?

man, i wish i had a picture of this

[NEUMANNZZ]

ive been reading along here cuz my abs light came on and has stayed on just the other day after i replaced the pads and rotors. i have a 95 silv 4x4 z71

so what do i need to do to adjust the sensor? just push on it?

man, i wish i had a picture of this

you should of seen it when you removed the rotors. they might need a good cleaning also.

[paoutsider]

you should of seen it when you removed the rotors. they might need a good cleaning also.

are you saying i have to pull the rotors to adjust these buggers?

[NEUMANNZZ]

yep.

[98GreenMachine]

yep.

the ABS sensor is actually behind a dust plate, and you don't really see it when doing the pads/rotors. Ive never had to adjust these sensors when doing brakes, they have nothing to do with the external braking system since the sensor is taking its readings from within the bearing assembly, not the metal ring on the CV.


I'm willing to bet that either your sensors are bad or your wheel bearings are on the way out. I had my ABS light on for awhile and i had a bad wheel bearing. Long story short, the grinding of the wheel bearing screwed up the sensor and after replacing the assembly, the ABS light went out and all was well.

[98GreenMachine]

usually with the light on the antilock system wont work. but your brakes will still work. might have to take it in to get it scanned for codes. to check for codes you will need a jumper wire. install the wire at the diagnostic link in terminal "H" and "A" for two seconds the remove. count the flashing lights. they should be 2 digit codes. ex: 2 flashes followed by 4 flashes is code 24. to reset the system turn on ignition put jumper wire in terminal "H" and "A" for two seconds then remove jumper wire. a good indication is when both the antilock and brake lamps light then turn off. let me know the results.

I would be genuinely surprised if the OBD1 system showed the ABS/brake codes. My OBD2 system showed nothing for the brake system when my ABS light was on solid for months..

[Reaper]

Actually, I was able to pull an ABS code from my '95 using the paper clip tool.

Found out which wheel speed sensor was giving me grief, then decided it wasn't worth $150 to make the light go out.

[Firestrike87]

I had the same problem. The light would turn on like 30 seconds after driving. It was a bad wheel speed sensor.

[98GreenMachine]

Actually, I was able to pull an ABS code from my '95 using the paper clip tool.

Found out which wheel speed sensor was giving me grief, then decided it wasn't worth $150 to make the light go out.

The sensor costs $150? thats nuts! You can buy a whole new bearing assembly that includes the sensor for ~$100


just as clarification, they are only used by the ABS system to determine when a wheel locks, they are not used to determine the vehicles speed.

The older system used a metal ring around the CV shaft with a sensor attached to that to determine wheel lock.

[Reaper]

Yeah $150 was the price I got for the whole bearing, since it doesn't look like you can get the sensor separately. You would think with all the problems we have with them, someone would figure out how to replace the sensor separately.